Non-unit protection technique for EHV transmission systems based on fault-generated noise. Part 2: signal processing

The paper describes the signal processing techniques developed for a new protection technique for EHV transmission lines. The signal processing unit, which forms a major part of the protection scheme, utilises fault-generated high-frequency signals derived from the signal measurement circuit to determine whether the fault is internal or external to the protected zone. The protection scheme has been designed using computer-aided techniques which closely emulate the hardware currently under development and which is being implemented using present-generation hardware